BrightSource Strikes World's Biggest Solar Energy Storage Deal

BrightSource Energy said Monday that it has struck a deal to add energy storage systems to three massive solar thermal power plants it will build to supply electricity to utility Southern California Edison.

Energy storage will allow the plants to operate into the night, meaning that BrightSource can now forgo building one 200-megawatt solar station that previously was needed to meet its obligation to generate 4 million megawatt-hours of electricity annually for the utility.

“It’s a huge advantage,” John Woolard, BrightSource’s chief executive, said in an interview Monday. “We came out very strongly with what I believe is the largest solar storage deal in the world.”

BrightSource spokesman Keely Wachs said in an e-mail that only six of the seven planned solar “power tower” stations will need to be built, saving some 1,280 acres of desert land. If approved by state regulators, the amended contracts with Southern California Edison will also result in lower costs for utility customers, the company said.

Both issues have come to the forefront as some environmentalists increasingly object to industrializing swaths of California’s Mojave Desert for solar power plants. Solar thermal developers, meanwhile, compete against ever-cheaper photovoltaic power plants as the price of solar modules continues to fall.

When four of the nine big solar thermal power plants approved by the California Energy Commission last year changed ownership, the new developers announced they would switch to solar panels like those found on residential rooftops and which convert sunlight directly into electricity.

BrightSource, on the other hand, has developed a new solar thermal technology that deploys vast arrays of mirrors called heliostats that focus the sun on a water-filled boiler that sits atop a tower. The intensive heat creates steam that drives an electricity-generating industrial turbine. Such solar thermal plants produce electricity more efficiently and consistently than photovoltaic stations, which are subject to fluctuations caused by passing clouds and other weather conditions and thus have less capacity to generate power.

For Southern California Edison, BrightSource will install a molten salt system called SolarPLUS that can store solar heat so it can be released to create steam after dark or when electricity demand spikes. The systems, which will come online in 2016 and 2017, will extend the operating time of the power plants by at least two hours, according to Woolard.

“It’s good from an environmental perspective and it lowers capital costs and permitting costs,” Woolard said, adding that he expected most solar thermal power plants completed after 2016 to feature energy storage.